Nasal creation and trouble shooting..?

Everything in connection with developing aircraft for FlightGear
User avatar
LesterBoffo
Posts: 766
Joined: Tue Sep 15, 2015 3:58 am
Location: Beautiful sunny, KOTH

Re: Nasal creation and trouble shooting..?

Postby LesterBoffo » Sun Nov 22, 2015 3:30 am

I'm sorry JWocky my apologies, I was getting a bit tired and seemed like I was repeating myself.

I'm beginning to think this problem may beyond the ken of either of us at present. Need to study what needs to be coded with what I've presently got.

User avatar
jwocky
Site Admin
Posts: 1833
Joined: Sat Sep 12, 2015 12:04 pm
Contact:

Re: Nasal creation and trouble shooting..?

Postby jwocky » Sun Nov 22, 2015 8:01 pm

If I put together what I read here, it looks to me as if you installed an additional dummy engine for fuel consumption and the idea is to conclude from a higher epr on a higher fuel consumption and build a Nasal to subtract fuel from the tanks?
Free speech can never be achieved by dictatorial measures!

User avatar
LesterBoffo
Posts: 766
Joined: Tue Sep 15, 2015 3:58 am
Location: Beautiful sunny, KOTH

Re: Nasal creation and trouble shooting..?

Postby LesterBoffo » Sun Nov 22, 2015 9:27 pm

No forget the fuel consumption, it's irrelevant, that part works like it's supposed to.

It's real simple I have a pressure source in the fdm, 'tapped' from the additional jet engine entry, it's a variable integer off the tree of engines/engine/epr. This sets up a property tree variable that runs from about 1.09 to 4.7 atmospheres from the jet engine's compressor, which is controlled inversely by the collective/throttle input.

I want to interpolate the epr output towards the rotor as power input in either ft pounds of torque or percentage of rotor torque. I think this is expressed as a RELTARGETTORQUE or some such in the control tree. Just a simple addition to the Nasal that interpolates a power level output based on the compressor's atmosphere.

That's as simple as I can explain it.

User avatar
jwocky
Site Admin
Posts: 1833
Joined: Sat Sep 12, 2015 12:04 pm
Contact:

Re: Nasal creation and trouble shooting..?

Postby jwocky » Mon Nov 23, 2015 11:24 pm

Too bad, I get from the flightgear-wiki again error 502. When they have it online again, you can look up the Nasal library there, it includes a function named interpolate. Otherwise you can use the simple three-step if your interpolation model is linear.

epr 0(or1 depends on the units you use) equals torque 1.09
epr max equals torque 4.70
what does epr x equal for torque?

4.70-1.09 = 3.61 actual range
So you need at least one reference value for torque at a given epr.

then
epr_base=1.09
torque_base=torque at epr_base
torque(epr)=torque_base/epr_base*(epr-epr_base)+torque_base

Code: Select all

var epr=getprop("from wherever your epr is in the tree");
var torque=torque_base/1.09*(epr-1.09)+torque_base;
setprop("wherever you want it", torque);
Free speech can never be achieved by dictatorial measures!


Return to “Aircraft Development”

Who is online

Users browsing this forum: No registered users and 28 guests